March 22 (Reuters) - The S&P and the Nasdaq reversed course to climb higher in afternoon trading on Wednesday, as investors sought bargains a day after the major indexes posted their biggest one-day loss since before the election.

Apple was up about 1 percent and provided the biggest boost to the three major indexes.

However, the Dow was lower, weighed down by a 6.3 percent fall in Nike after the world’s largest footwear maker missed quarterly revenue estimates.

“What we’re seeing today is buyers being opportunistic and trying to gain entry into the overall market,” said Robert Pavlik, chief market strategist at Boston Private Wealth in New York.

“That’s why we’re seeing tech and industrials stocks, which last a lot on Tuesday, lead today.”

Still, the market remained cautious ahead of the first major legislative test of Donald Trump’s presidency.

Investors are closely watching the outcome of the healthcare bill, which Republican party leaders are aiming to move in the House as early as Thursday, as a signal to how Trump can push forward his tax cuts and simpler regulation agenda.

Trump has been trying to rally Republican lawmakers behind the plan, which will dismantle Obamacare.

Some investors fear that if the healthcare reform act runs into trouble or takes longer-than-expected to pass, then Trump’s tax reform policies may face setbacks.

“The market was giving Trump somewhat of a talk-the-talk leeway,” said Ryan Larson, head of U.S. equity trading at RBC Global Asset Management in Chicago.

“It was supportive of what the administration was talking about. We’re starting to get into a phase where that grace period is coming to an end and what the market wants to see more walk-the-talk as opposed to talk-the-talk.”